A simple one-step assay platform based on fluorescence quenching of macroporous silicon

• Published in: Biosensors & bioelectronics Vol. 41; pp. 477 - 483
• Main Authors: Yoo, Lina, Ahn, Keum-Young, Ahn, Ji-Young, Laurell, Thomas, Lee, Yong Man, Yoo, Pil J., Lee, Jeewon
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.03.2013; Elsevier
• Subjects: adenosine; Adenosine - analysis; Adenosine - genetics; adsorption; Aptamers, Nucleotide - chemistry; Aptamers, Nucleotide - genetics; Biological and medical sciences; Biosensing Techniques - instrumentation; biosensors; Biotechnology; complementary DNA; dissociation; electrochemistry; Engineering and Technology; Equipment Design; Equipment Failure Analysis; fluorescence; Fluorescence quenching; Fundamental and applied biological sciences. Psychology; hybridization; Macroporous silicon; Medical Engineering; Medicinteknik; nucleotide sequences; oligonucleotides; polystyrenes; Porosity; Reproducibility of Results; Sensitivity and Specificity; silicon; Silicon - chemistry; Simple one-step assay; Spectrometry, Fluorescence - instrumentation; streptavidin; Teknik; zinc oxide; Macroporous silicon; Simple one-step assay; Fluorescence quenching; Fluorescence; Silicon
• ISSN: 0956-5663; 1873-4235; 1873-4235
• DOI: 10.1016/j.bios.2012.09.012

We synthesized 3D macroporous silicon through a simple electrochemical dissolution process and systematically estimated its protein adsorption and effect on fluorescence emission. Compared with conventional 2D polystyrene plate, the macroporous silicon showed a superior protein adsorption capacity and significant fluorescence quenching effect. We developed a 3D macroporous silicon-based adenosine assay system through the following fabrication process: streptavidin molecules that have been immobilized on the surface of macroporous silicon are attached with biotin-linked and adenosine-specific DNA aptamer, followed by hybridization between the attached aptamer and fluorescent chemical (carboxytetramethylrhodamine/CTMR) that is conjugated with a short complementary DNA sequence. In the absence of adenosine, the aptamer-CTMR complexes remain closely attached to the surface of porous silicon, hence fluorescence being significantly quenched. Upon binding to adenosine, the DNA aptamer is subject to structure switching that leads to dissociation of CTMR from DNA aptamer, and consequently the CTMR fluorescence is restored, indicating a simple one-step assay of adenosine. Compared to the conventional 2D PS and ZnO nanorods-based assays, adenosine at much lower (sub-micromolar) concentration was successfully detected through the 3D macroporous silicon-based assay. The three-dimensionally and densely immobilized aptamer probes and effective fluorescence quenching on the surface of macroporous silicon enables adenosine to be detected at lower levels. Although the adenosine detection is reported here as a proof-of-concept, the developed macroporous silicon-based simple one-step assay platform can be applied in general to fluorescence quenching -based detection of many other biomolecules. ► The macroporous silicon was synthesized through electrochemical dissolution process. ► It showed a superior protein binding capacity and fluorescence quenching effect. ► The macroporous silicon was used as a fluorescence quencher for aptamer sensor. ► This simple one-step assay system detected adenosine at sub-micromolar concentration.